Thin film transistor liquid crystal display (TFT-LCD) is featured with small size, low power consumption, no-radiation and the like, and thus dominates the current flat-panel display market.
In the TFT-LCD, a source electrode and a drain electrode of the TFT are electrically connected with each other through a semiconductor channel in the case that a high level is applied to a gate electrode of the TFT, and a data signal from a data line is applied to a pixel electrode through the TFT. Total capacitance of the TFT=Cgs+Cchannel+Cgd, wherein Cgs represents a capacitance formed due to an overlapping of the gate electrode and the source electrode, and Cgd is capacitance formed due to an overlapping of the gate electrode and the drain electrode. It is expected that both Cgs and Cgd are equal to 0, so as to reduce the total capacitance of the TFT. However, at present, the source electrode and the drain electrode inevitably overlap with the gate electrode, because electrical properties of the TFT will be affected if a gap between the source electrode and the drain electrode is large. In addition, among a plurality of TFTs, relative positions of the source electrode and the drain electrode with respect to the gate electrode are nonuniform, and thus Cgs and Cgd among the TFTs are different and the TFTs are different from one another in the total capacitances. In this case, the pixel electrodes are charged with different voltages even though the same data signal is applied, which will cause an uneven chrominance when an image is displayed by the liquid crystal display. In addition, a driving voltage of the TFT is increased due to the existence of Cgs and Cgd, and thus the duration required by the charging process is increased.